The Slippery Facts About Lubricants

When it comes to sex, sometimes we need a little help making things go, well, smoothly. Enter lubricants, also known as “personal lubricants” or, colloquially, “lube.” Lubricant can make intercourse more comfortable for women with vaginal dryness, a common problem that can stem from a variety of causes, including falling estrogen levels at menopause, emotional factors, or certain medications. It also helps for women who do not naturally moisten when aroused. Lubricant also makes it easier—and more pleasurable—to use condoms, a must for protecting against sexually transmitted diseases.

A 2014 Indiana University study found that 65 percent of women have used lubricant to make sex more comfortable, more pleasurable, or both. And in a survey of gay men in San Francisco who have anal intercourse, 89 percent said they always use lubricant during sex. But despite lubricants’ ubiquity and mostly benign reputation, research in the last several years has raised questions about the safety of some products—especially for certain groups of users. Here’s what you need to know about the potential problems and how to protect yourself if you’re a lubricant user.

How safe are lubricants?

Conventional wisdom has held that lubricant reduces the chance of sexually transmitted infections by making the vaginal or anal area more slippery, thus cutting down on the risk of tiny tears that promote the transmission of infectious agents. But a 2012 report in the journal Sexually Transmitted Diseases found that men and women who had used lubricants for anal intercourse in the previous month were actually more likely to test positive for gonorrhea or chlamydia than those who had anal sex without lube. The authors proposed that the observed increased risk may have been because the lubricants caused inflammation of the anus and rectum, making it easier for organisms to spread.

In addition, a 2014 lab study in the journal Pharmaceutics tested 12 lubricants sold in Europe (including popular brands such as K-Y Jelly and Replens) and found that some of them might alter the pH balance of the vagina, which in theory could increase the risk of certain vaginal infections. (The study didn't look at infection rates, just at the chemical composition of the lubricants.) And a UCLA study published in 2013 found that women who used petroleum jelly or baby oil as a lubricant were especially likely to end up with bacterial vaginosis or a yeast infection. So much for pleasure.

None of these studies definitively establishes that sexual lubricants directly cause any type of infection. But they underscore the importance of using condoms, which are the surest way to prevent STDs (other than abstinence or a monogamous relationship with a monogamous partner). That’s true whether you use lubricant or not. And if you’re a woman and develop a vaginal infection after using a lubricant, you may want to consider trying a different product—or going without lubricant for a while.

Other lubricant caveats

Even if infection isn’t a concern, commercial lubricants can contain ingredients that could cause irritation or allergic reactions in some people. Particularly common culprits include “numbing” lubricants that contain benzocaine, a topical anesthetic (Anal-ese and Climax Control are two examples), and “warming” lubricants, which may feature menthol or capsaicin (the same ingredient in hot peppers). As in other skin products, lubricants that include fragrance or flavoring ingredients may irritate sensitive skin. Other potential irritants include the antibacterial agent chlorhexidine, propylene glycol, glycerin, and a group of preservatives called parabens (often listed as methy-, butyl-, ethyl- and propyl-paraben).

You can determine if you’re sensitive to a given product by dabbing a bit on the inside of your elbow and waiting a day to make sure no redness occurs. If you have an unusual reaction to a new lubricant, stop using it; if the problem persists, talk to your doctor.

Two other caveats: Oil-based lubricants can degrade latex and should never be used with latex condoms. That includes natural lubricants like mineral oil and baby oil as well as commercial oil-based products. Finally, there’s preliminary evidence that certain water-based lubricants, including Astroglide and several K-Y products, might decrease sperm motility, though there isn’t evidence that people who use them have lower rates of pregnancy.

Bottom line: Although research is ongoing, over-the-counter personal lubricants are generally safe for most people if used as directed, and they can be a good solution for vaginal dryness or otherwise reducing friction (or boosting pleasure) in your sex life. But as with anything you put in your body, take precautions: Read the label, avoid products with ingredients to which you know you’re sensitive (as a general rule, the fewer the ingredients, the better), use products as directed, and be on the lookout for unpleasant reactions. For tips on which lubricant makes the most sense for you, see How to Choose a Sexual Lubricant.